The Float is a good shock. I suspect that it is not properly tuned to match the suspension characteristics of your bike though . While you can adjust the air pressure and turn the rebound dial on the Float R, there are a number of ways that the shock manufacturers optimize their shocks to work with various suspension designs.
For instance, I believe that Fox makes 3 different sizes of air sleeves for their Float shock. If the Fox shock on your bike has the small air canister, but the Swinger shock had a large one, the bike would ride much differently. If the air can is too large, you can reduce your shock’s air volume with this kit as explained on Pinkbike.
But there’s more. My Float R shock has a sticker that says “Propedal Tune” and mine indicated one (shortest) bar out of three, like a cell phone signal indicator. I believe that this means that my shock is tuned for minimal low speed compression, which Fox and the bike manufacturer felt worked best with the rear suspension design of my bike. Other suspensions designs would be better with mediun (2 bars) or maximum (3 bars) of low speed compression. There are other things that can be tuned as well; the shock in the Pinkbike article has stickers for boost valve and rebound tune, each with a number (instead of the bar graphic like my shock) next to them.
The bottom line is that without knowing how the Radium shock is tuned, it would be a crapshoot on whether it works better or worse than the Fox. If you went to someone who is knowlegable on suspension tuning, they could probably make your shock work better or tell you which one you should buy if they can’t.
